1. Field of the Invention
This invention relates generally to an improved flange for coupling various fittings to an object having external sidewalls and a normally closed interior containing a liquid and, specifically, to an improved flange for coupling various fittings to a water heater/boiler tank, piping or related plumbing components.
2. Description of the Prior Art
Water heaters and boilers include a tank which is provided with a plurality of tank openings for attaching pipes, heating elements and similar fittings to the tank. For example, a typical water heater is provided with an inlet valve, a drain valve, and an ASME rated relief valve, among other fittings.
In the past, the tank opening or port typically had a flange welded on for receiving the various tank fittings. The excessive heat used in the welding process often caused the flange to distort, leading to sealing problems and premature failure in use. In addition, the manufacturing steps involved in welding a flange were time consuming and relatively expensive.
The present invention has as its object to provide a bolt-on fitting for a tank opening of a water heater or boiler, or a bolt-on fitting for other related piping or plumbing components, such as a bolt-on fitting for an opening provided in a transfer pipe running to or from a water heater tank.
Another object of the invention is to provide such a flange which is sealed by means of an O-ring seal carried on an inner surface of the flange between the flange and the mating surface of the object to which the flange is attached.
Another object of the invention is to provide a bolt-on flange with a double curved inner surface adapted to mate with either a cylindrical sidewall or a spherical surface.
Additional objects, features and advantages will be apparent in the written description which follows.